A well-known and effective method for packaging pharmaceutical products and other sterile products employs machinery to automatically form a container, fill the container with the product, and then hermetically seal the product within the molded container. This process can be carried out by a "form-fill-seal machine" for which designs are known. See, for example, U.S. Pat. No. 3,597,793 to Weiler, U.S. Pat. No. 3,919,374 to Komendowski, U.S. Pat. No. 4,176,153 to Weiler et al., U.S. Pat. No. 4,178,976 to Weiler et al., U.S. Pat. No. 4,707,966 to Weiler et al., and patents cited therein.
In this packaging method, described in the patents identified above, a length of parison is extruded from an extruder head in the form of a vertically oriented, elongated, hollow tube of semi-molten thermoplastic material (i.e., in a plastic state). Before, during, or after the parison is extruded to the desired length, a split mold assembly of two main mold halves is positioned in spaced relationship from and around the parison.
Next, with collapse of the upper end of the parison prevented by holding jaws, the parison is severed, above holding jaws and below the extruder head, in a conventional manner (e.g., by means of a moving cutter, such as a hot wire or the like).
The main mold halves are then moved together to a closed position, and in this position cooperate to define a cavity for the container around the parison.
The closed mold assembly is then moved away from the extruder head to a molding, filling, and sealing station. Molding can be effected by blow forming, vacuum forming, or a combination of both of the foregoing expedients depending on container size. Typically, a vertically reciprocable composite blowing and filling mandrel is provided in registry with the opening at the upper end of the severed length of the parison. The mandrel is extended downwardly into the opening of the upper end of the severed length of the parison to seal the parison opening with the mandrel and to press the parison against the mold. The mandrel includes a blowing tube and a filling tube.
In operation, compressed gas, such as air or the like, is discharged through the mandrel blowing tube into the interior of the hollow parison to inflate the parison outwardly against the walls of the cavity (with or without vacuum assist through small passageways in the molds), and this forms the container body.
Next, the filling tube inside the composite mandrel is reciprocated downwardly to open a vent passage in the mandrel to permit venting of the compressed gas out of the molded container. Subsequently, the blowing tube is moved downwardly a small amount within the mandrel to open the product dispensing valve and permit the product to be injected under pressure from the filling tube into the formed container.
After the formed container has been filled with the desired amount of product, the composite mandrel is withdrawn from the open of the parison. The top of the open container is then sealed by moving sealing molds together to hermetically seal the top of the formed container. If desired, an insert, such as a dispensing nozzle, rubber stopper, or the like, can be incorporated in the top of the container as taught by, for example, U.S. Pat. No. 4,821,897.
After the top of the container has been sealed, the sealing molds and main mold halves are opened to expose the completed container so that the container can be removed. In large scale production applications, a plurality of containers are typically formed in a single mold assembly. Such a mold assembly defines a plurality of mold cavities and is adapted to cooperate with a plurality of extruder heads, holding jaws, blowing and filling mandrels, and sealing molds. The parisons are typically extruded in a spaced-apart line between the main mold halves. When the main mold halves close, the thermoplastic material is spread between the parisons, and the containers are molded within a unitary connecting web, carrier, or card of thermoplastic material.
Prior art expedients for the removal of a container card from the mold assembly are shown in FIGS. 1-4. Specifically, FIG. 1 illustrates such a container carrier or card 30, and FIG. 2 shows the card 30 in a closed mold assembly 40 after the containers, in the form of small vials 36, have been formed between main mold halves 42 and 44, then filled with product, and finally sealed between sealing mold halves 46 and 48.
The production of a plurality of containers at one time in a single mold assembly is especially suitable for the manufacture of small vials of a sterile product. For example, for a 1 ml container size, five such containers may be formed in a side-by-side array from one parison (the parison being shown in FIG. 1 as having a flattened, solidified configuration 50 in the molded card 30). Three or four such parisons may be positioned simultaneously in a side-by-side array within a single mold assembly 40 to produce the molded composite article or card 30 with a total of 15 or 20 molded containers 36 carried therein. Such a conventional carrier or card 30 may have, for example, a length of about 14 inches and a height of about six or seven inches.
Each of the formed, filled, and sealed containers 36 is connected, about its periphery on the parting plane to the carrier or card 30 by frangible, reduced thickness portions of the thermoplastic material. The containers 36 can be removed from the card 30 by punching, knocking, or pushing the containers so as to break the reduced thickness sections. This is typically accomplished at conventional "deflashing" stations downstream from the mold assembly.
With reference to FIGS. 1 and 2, the vertical location of the top of the container structure is designated as Y3 and the vertical location of the bottom of the container structure is designated as Y2. The distance between Y2 and Y3 typically is constant along the length of the card 30.
In order to accurately knock the containers 36 out of the card 30, positions of the containers 36 relative to the surrounding card 30 must be established. This can be done automatically by providing one or more defined reference surfaces on the card 30 which can be engaged by the processing apparatus.
When the containers 36 are molded with the card 30 in the mold assembly, the tops and bottoms of the parisons typically project beyond the mold cavities and are irregularly deformed as mold flash, such as top flash 53 and bottom flash 54 (FIG. 1). The mold flash does not have any flat surface or other uniform surface which can be used to define a reference position. Thus, the vertical distance from the edge of the flash to an adjacent container 36 carried in the card 30 is not constant along the length of the card 30. That is, with reference to FIGS. 1 and 2, the elevation Y4 of the top of the upper flash 53 and the elevation Y0 of the bottom of the lower flash 54 are vertically variable along the length of the card 30. It is thus not possible to establish a uniform vertical distance from either the top or bottom edge of the card flash to the containers 36 for purposes of vertically aligning deflashing apparatus or knock-out devices for knocking the containers out of the card 30.
A conventional process attempts to solve this problem by providing a uniform surface in the bottom flash 54. Specifically, as shown in FIG. 2, the flash 54 extending below the molded containers 36 in the carrier or card 30 is molded with a straight, frangible web 58 oriented parallel to the bottoms of the containers 36 and located at an elevation Y1 which is a predetermined distance below the container bottoms at Y2. Further, the portion of the parison below the frangible web 58 is molded around upwardly projecting carrier pins 60. Thus, after the mold assembly 40 is opened, the card 30 along with the containers 36 therein, remains held by the pins 60 along the bottom edge of the flash 54 below the frangible web 58. Clamping members 64 (FIG. 3) then grip the top of the card 30 and hold it while the pins 60 are moved downwardly to tear off the bottom portion of the card flash 54 at the frangible web 58 to leave a substantially straight surface 58A along the bottom of the remaining card portion.
FIG. 3 shows the pins 60 pulling the bottom flash 54 downwardly in the direction of the arrow 68 and away from the remaining portion of the card 30. The pins 60 are aligned to move through holes 70 in a stripper plate 72 so that the flash 54 will be stripped off of the pins 60 by the plate 72 as the pins 60 are lowered below the plate 72. A sweeper bar assembly 76 is provided to sweep the loose flash 54 into a suitable receiving bin (not illustrated).
The card 30 can then be transferred to a remote station where further deflashing operations can be performed utilizing the surface 58A on the bottom of the card as a reference. To this end, the card 30 is deposited on a belt conveyor 80 (FIGS. 3 and 4) by the clamping members 64 so that the straight reference surface 58A rests on the conveyor belt. Suitable lateral guides 84 maintain the card 30 in a vertical orientation so that the vertical distance between the bottom of the card 30 on the conveyor and the containers 36 remains a constant, known amount and can be used for vertical alignment or registration of additional deflashing apparatus or container removal apparatus (not illustrated).
The lengthwise (i.e., horizontal) alignment of the card 30 can be established from a vertical reference surface 90A on the card 30 (FIG. 3). This vertical reference surface 90A is created along with the horizontal reference surface 58A when the bottom flash 54 is torn away from the card 30 by the pins 60. To this end, the card frangible web 58 (FIG. 1) is initially molded with a right angle shaped frangible web 90 offset from the horizontal web 58 (FIG. 1).
While the above-described process for producing flat reference surfaces at the bottom of a carrier or card works satisfactorily in the specific applications which it was designed, it does not work well with all types of thermoplastic materials. Further, the process can lead to the formation of particulate matter or other waste pieces which are generated by the tearing away of the bottom flash along the frangible web. This is not desirable in "clean room" production facilities where a sterile product is hermetically sealed within the containers by the molding, filling, and sealing machine.
Accordingly, it would be beneficial to provide an improved thermoplastic carrier/product structure which could be removed from a clean room environment after molding for further processing without first requiring deflashing operations or other operations in which the thermoplastic material is ruptured or severed.
Further, it would be beneficial if an improved method could be provided to readily accommodate the formation of a reference surface on the molded article without requiring deflashing operations at the mold assembly in a clean room environment.
In particular, it would be advantageous if such an improved system could provide a molded article with a uniform height so that further processing operations could be conducted with proper registration of the article at locations remote from the molding machine.
Further, it would be desirable to provide such an improved system with the capability for accommodating a variation in parison length as the parison is extruded between open mold halves.
It would also be desirable to provide a system for reducing the amount of thermoplastic material required for the carrier in which the containers are molded. With a conventional pin assembly having pins 60 as described above with reference to FIG. 3, the pins 60 must be relatively long and must engage a relatively long length of parison below the molded containers. This is necessary to establish a sufficient gripping engagement between the pins 60 and the thermoplastic material which can withstand the subsequent forces that are generated when the pins are lowered to pull the lower flash 54 away from the remaining portion of the card 30. This requires the use of a significant amount of thermoplastic material which ultimately may end up as discarded waste.
Another salutary feature of such an improved system would be its capability for accommodating various thermoplastic materials, such as high density polyethylene and polypropylene. While the use of long pins 60 works satisfactorily with some thermoplastic materials, such as low density polyethylene, it does not work well with other thermoplastic materials. For example, high density polyethylene and polypropylene exhibit greater strength and resistance to rupture at the frangible web 58. Excessive force is required to move the pins 60 downwardly in an attempt to break the high density polyethylene or polypropylene material at the frangible web. Even then, the break is not clean and straight. Thus, the desired flat reference surface is not easily formed with this kind of system when used with polypropylene and high density polyethylene.
It would also be advantageous to provide an improved system for forming the thermoplastic material in the card around the containers and in the peripheral flash with improved, and predictable, handling and severing characteristics. To this end, the system should provide an improved flow distribution of the thermoplastic material and an improved structure to accommodate the cooling of the molded material.
The present invention provides an improved article with a position-defining structure which can accommodate designs having the above-discussed benefits and features. Further, the present invention also provides an improved method and apparatus for making and processing such an article in ways which incorporate or exhibit the foregoing benefits and desired capabilities.